According to a new study, grouches don’t necessarily remain grouches for the rest of their lives.

Findings published in the journal Social Indicators Research suggest that people’s personalities can change over time just as much as external factors like change in jobs or income, or marriage or divorce.

The researchers, of the University of Manchester’s School of Psychological Sciences, said that the findings indicate we can increase our well-being not just through these actual external changes, but also through changes in our personalities.

“The focus of many wellbeing studies in economics is on how changes to our circumstances, such as a higher income, getting married or a different job might influence our wellbeing. The influence of our personality is often ignored in these types of studies in the belief that our personality can’t or doesn’t change,” study researcher Dr. Chris Boyce said in a statement. “We show that personality can and does change and, not only is it more likely to change than an income increase, it contributes much more to changes in our wellbeing.”